Invasive green crabs destroying shellfish resources, intertidal habitat

I admit it.  I was a skeptic.  How could one little critter cause so much devastation – and apparently overnight?  Not surprisingly, the warning bell being sounded by harvesters was warranted.  I was converted the minute I saw with my own eyes evidence of the green crab’s destructive powers in Freeport, ME in August of 2013.

In addition to clear proof of heavy predation on bivalve shellfish populations, the invasive European green crab seems to impact the entire nearshore coastal ecosystem and is currently having a significant effect on coastal Maine and throughout New England and Maritime Canada.


Currently, the vast and ravenous green crab population is by far and away the greatest cause of bivalve shellfish mortality. (Kohl Kanwit photo)

Green crabs are voracious predators that preferentially consume valuable commercial shellfish resources, including softshell clams, mussels, oysters, and hard clams.

They destroy fringe marsh habitat by burrowing into the banks and eating plant roots from the underside, leading to erosion in a single season that normally would take decades, according to Dr. Daniel Belknap of the University of Maine.  They have wiped out entire intertidal and subtidal eelgrass beds to the stunned amazement of people who observed the phenomenon in 2013, including Dr. Hilary Neckles of the US Geological Survey and Dr. Jane Disney of Mount Desert Island Biological Laboratory…




CFN_3_14coverRead the rest and much, much more in the March issue of Commercial Fisheries News.

Read online immediately and download for future reference.